The South Coast Air Quality Management District’s Refinery Committee also directed the agency’s staff to find out more about an additive in the acid used to reduce the risk of creating a toxic gas cloud during an accidental release, including the level currently in use at the two refineries. The committee wants a report back on the issues in 90 days.

The two South Bay refineries are the only ones in the state still using the potentially lethal chemical.

Board member Joe Lyou, president and chief executive officer of nonprofit group The Coalition for Clean Air, characterized the committee’s position in not recommending a ban as simply not possessing sufficient information.

“I wish alternative technologies (to using hydrofluoric acid) were further along,” he said. “I don’t think they’re at a place we can mandate (using them).”

At least one board member said he was reticent to phase out use of the chemical now because the potential cost in the hundreds of millions of dollars could mean closure of the twin refineries, which employ hundreds of workers.

The board’s mid-afternoon decision came at the end of a lengthy meeting Saturday at Torrance City Hall attended by more than 500 local residents and blue-clad refinery workers.

Hydrofluoric acid is considered one of the world’s most dangerous chemicals, capable of forming a toxic gas cloud if it is inadvertently released, experts say. It is so “highly hazardous” it’s basically considered a “systemic poison,” UCLA professor and chemical safety expert Craig Merlic told the board.

The modified form of the chemical in use locally possesses an additive that inhibits the formation of a toxic gas cloud, but at most only provides a 30 percent reduction – and likely less – in its size, AQMD staff said.

That was largely why the board directed staff to discuss the additional safety measures with the two refineries, which will include enhancements to current safety measures such as more automated systems in the event of an accidental release and increased HF monitoring.

It was clear many on the board had reservations about the continued use of HF, with Rolling Hills Estates Councilwoman Judy Mitchell being the most blunt.

“A risk well-managed may well be a risk too great,” she said, echoing the title of a study published a few years ago that advocated getting rid of HF. “In my opinion, it is an unacceptable risk.”

A lack of information about the properties of HF, a proprietary chemical manufactured by Honeywell, hampered the board’s ability to reach any decision, several panelists said.

“We want to find out from Honeywell the minimum percentage of additive needed to mitigate the risk of an accidental release,” said Sam Atwood, AQMD spokesman, after the meeting.

Board members were frustrated that it appeared no one had tested the modified hydrofluoric acid’s capability of providing an increased level of safety and that answers to some basic questions about the chemical were unavailable. That was in part due to trade secrets, but also was related to the “extreme challenge” posed by conducting tests on such a hazardous chemical, AQMD staff said.

“To have the comfort of hard data, we don’t have that,” conceded Wayne Nastri, AQMD chief executive officer, who admitted the agency didn’t know for sure the percentage of additive employed at the refineries.